Island – the Island back-end, supports building CPU-native projects for Window, Linux, Darwin (Apple macOS, iOS, tvOS and watchOS) and the native Android NDK, as well as WebAssembly projects that run in the browser.

Cooper – the Cooper back-end compiles projects the Java Runtime, and related platforms, including Android. Your code will be compiled to Java byte code that can run in the JVM, and possibly post-processed from there for Android and other sub-platforms.

Toffee – the legacy Toffee back-end compiles for Cocoa platform and the Objective-C runtime employed by Apple's operating systems. In time, it will be fully replaced by the Island/Darwin back-end.

Gotham – "Gotham" is the code name for a new target (meta-)platform for cross-platform library development that we are working on for the Elements compiler; it is currently in internal development and not quite ready for external testing, but it will be in alpha/beta in 2019/2020.